There is a need for an early seek of a disk. In particular, in an iterative decoding scheme represented by a low-density parity-check (LDPC) code, a few sectors to tens of sectors of a decoding delay occurs until a desired sector is read and then a read channel transmits data to a hard disk controller (HDC). Accordingly, when continuously reading data present in another zone or cylinder, a controller needs to wait for a decoding delay until a seek for a subsequent destination position is initiated. Accordingly, a random read performance may be degraded.
In relation thereto, for example, JP-A-62-121527 discloses parallel processing of a data transmission between a memory and a buffer, and providing a wrap-around function to a reading/recording operation of the buffer, and performing a serial or parallel processing of a data transmission between a main memory and the buffer even while data is being transmitted between the buffer and the disk, in the seek of the disk.
However, there is a need for a technology capable of improving a random read performance through an early seek.